Potential pleiotropic effects of Mpdz on vulnerability to seizures.

We previously mapped quantitative trait loci (QTL) responsible for approximately 26% of the genetic variance in acute alcohol and barbiturate (i.e., pentobarbital) withdrawal convulsion liability to a < 1 cM (1.8 Mb) interval of mouse chromosome 4. To date, Mpdz, which encodes the multiple PSD95/DLG/ZO-1 (PDZ) domain protein (MPDZ), is the only gene within the interval shown to have allelic variants that differ in coding sequence and/or expression, making it a strong candidate gene for the QTL. Previous work indicates that Mpdz haplotypes in standard mouse strains encode distinct protein variants (MPDZ1-3), and that MPDZ status is genetically correlated with severity of withdrawal from alcohol and pentobarbital. Here, we report that MPDZ status cosegregates with withdrawal convulsion severity in lines of mice selectively bred for phenotypic differences in severity of acute withdrawal from alcohol [i.e., High Alcohol Withdrawal (HAW) and Low Alcohol Withdrawal (LAW) lines] or pentobarbital [High Pentobarbital Withdrawal (HPW) and Low Pentobarbital Withdrawal (LPW) lines]. These analyses confirm that MPDZ status is associated with severity of alcohol and pentobarbital withdrawal convulsions. Using a panel of standard inbred strains of mice, we assessed the association between MPDZ status with seizures induced by nine chemiconvulsants. Our results show that MPDZ status is genetically correlated with seizure sensitivity to pentylenetetrazol, kainate and other chemiconvulsants. Our results provide evidence that Mpdz may have pleiotropic effects on multiple seizure phenotypes, including seizures associated with withdrawal from two classes of central nervous system (CNS) depressants and sensitivity to specific chemiconvulsants that affect glutaminergic and GABAergic neurotransmission.

Accumulation of mRNA coding for the ctf13p kinetochore subunit of Saccharomyces cerevisiae depends on the same factors that promote rapid decay of nonsense mRNAs.

The CTF13 gene codes for a subunit of the kinetochore in Saccharomyces cerevisiae. The temperature-sensitive mutation ctf13-30, which confers reduced fidelity of chromosome transmission, is a G --> A transition causing an amino acid substitution of Lys for Glu146. Strains carrying one chromosomal copy of ctf13-30 fail to grow at the restrictive temperature, whereas a haploid strain carrying two copies of ctf13-30 can grow. Four genes, UPF1, UPF2, UPF3, and ICK1, were represented among extragenic suppressors of ctf13-30. The UPF genes encode proteins that promote rapid decay of pre-mRNAs and mRNAs containing a premature stop codon. Suppressor mutations in these genes restore kinetochore function by causing increased accumulation of ctf13-30 mRNA. They also cause increased accumulation of CYH2 pre-mRNA, which is a natural target of UPF-mediated decay. Mutations in ICK1 restore kinetochore function but have no effect on ctf13-30 mRNA or CYH2 pre-mRNA accumulation. Most importantly, loss of UPF1 function causes increased accumulation of wild-type CTF13 mRNA but has no effect on the mRNA half-life. We propose that UPF-mediated decay modulates the mRNA level of one or more factors involved in CTF13 mRNA expression.

A factor required for nonsense-mediated mRNA decay in yeast is exported from the nucleus to the cytoplasm by a nuclear export signal sequence.

In Saccharomyces cerevisiae, Upf3p is required for nonsense-mediated mRNA decay (NMD). Although localized primarily in the cytoplasm, Upf3p contains three sequence elements that resemble nuclear localization signals (NLSs) and two sequence elements that resemble nuclear export signals (NESs). We found that a cytoplasmic reporter protein localized to the nucleus when fused to any one of the three NLS-like sequences of Upf3p. A nuclear reporter protein localized to the cytoplasm when fused to one of the NES-like sequences (NES-A). We present evidence that NES-A functions to signal the export of Upf3p from the nucleus. Combined alanine substitutions in the NES-A element caused a re-distribution of Upf3p to a subnuclear location identified as the nucleolus and conferred an Nmd- phenotype. Single mutations in NES-A failed to affect the distribution of Upf3p and were Nmd+. When an NES element from HIV-1 Rev was inserted near the C terminus of a mutant Upf3p containing multiple mutations in NES-A, the cytoplasmic distribution typical of wild-type Upf3p was restored but the cells remained phenotypically Nmd-. These results suggest that NES-A is a functional nuclear export signal. Combined mutations in NES-A may cause multiple defects in protein function leading to an Nmd- phenotype even when export is restored.

Left ventricular performance following the arterial switch operation: use of noninvasive wall stress analysis in the postoperative period.

OBJECTIVE: To determine postoperative left ventricular mechanics following the arterial switch operation (ASO). DESIGN: Prospective, cohort study. SETTING: Pediatric cardiac recovery room. PATIENTS: Nine neonates with transposition of the great arteries undergoing the ASO within the first week of life. INTERVENTIONS: Noninvasive ejection phase indices: shortening fraction (% SF), corrected mean velocity of circumferential shortening (VCFc), and wall stress analysis were used to calculate indices of specific left ventricular systolic mechanics. The % SF and VCFc were respectively adjusted for left ventricular afterload (end-systolic wall stress) to derive an index for left ventricular performance (stress-shortening relation) and contractility (stress-velocity relation). Left ventricular preload was assessed as the variance between the performance and contractility indices. All indexed data are reported as mean Zscore (i.e., number of standard deviations from the mean of a normal age- and body surface area-adjusted population). A mean Zscore of < -2 or > 2 was regarded as a significant variance from normal. Transmitral Doppler flow patterns were recorded at each postoperative interval and analyzed for isovolumic relaxation time (IVRT) as an index of left ventricular compliance. MEASUREMENTS AND MAIN RESULTS: All nine patients did well clinically and completed the study. Noninvasive parameters were measured at mean intervals of 3 (early), 23 (intermediate), and 48 hrs (late postoperative) relative to the time of arrival in the cardiac recovery room. Postoperative left ventricular performance was decreased throughout the early (-4.0 +/- 1.5 SD), intermediate (-4.1 +/- 2.8), and late (-3.5 +/- 1.3) phases of recovery. In contrast, the overall left ventricular contractility remained normal throughout the three postoperative intervals (0.2 +/- 1.8, -1.2 +/- 1.9, and -1.0 +/- 1.6, respectively), although three of the nine patients had a diminished stress-velocity index during the study period. Left ventricular afterload was within normal range in the early (0.1 +/- 1.7) and intermediate (1.5 +/- 1.9) phases of recovery, but increased in the late postoperative period (2.5 +/- 2.9). Left ventricular preload was decreased significantly throughout the early (-4.2 +/- 1.3), intermediate (-2.8 +/- 2.0), and late (-2.5 +/- 1.0) postoperative phases. All nine patients demonstrated decreased preload during the recovery period. IVRT was decreased in the post-ASO patients at each phase of recovery compared with normal data (p < .001). CONCLUSIONS: Left ventricular performance is impaired in infants during the period immediately following the ASO. A persistent preload deficit closely matches the pattern of impaired ventricular performance. Decreased IVRT points to impaired ventricular compliance as the etiology of the altered preload. In contrast, left ventricular contractility remains normal in the majority of post-ASO patients. Decreased contractility may account for impaired ventricular performance in selected cases.

Tissue protein and energy deposition in steers fed isocaloric diets with different levels of nitrogen.

Metabolism and comparative slaughter feedlot trials were conducted with 85 Angus-Hereford crossbred steers to evaluate effects of isocaloric diets with five levels of N on protein and energy deposition in tissues. The diets had Urea Fermentation Potentials (UFP) of 3.8, 1.2, -1.4, -3.9 and -6.9 and metabolizable protein (MP) levels of 69.2, 76.6, 80.1, 80.8 and 80.0 g/kg dry matter, respectively, with increasing dietary N levels. Crude protein digestibility increased (P less than .005) with increasing N levels, but total digestible nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) showed no significant relationship to variation in N level. Metabolism trial N and energy utilization indicates that N to energy balance occurred at zero to slightly negative UFP. In the feedlot trial, average daily gain, ME intake, dry matter intake and energy gain increased with increasing dietary MP level. Daily gains in empty body fat and energy and carcass characteristics indicating increased finish also increased with increasing MP level. However, empty body protein gain increased with increased N level and indicated that in isocaloric diets, urea-N could replace a portion of the plant protein without decreasing tissue protein gains. The results support the UFP system for determining N to energy balance in feedlot diet.

Nutritive value of methane fermentation residue in diets fed to feedlot steers.

Nutritive value of the methane fermentation residue (MFR) from the effluent of a large scale thermophilic methane generator was determined in diets fed to feedlot steers. The MFR contained 22.2% dry matter and 21.9% crude protein (dry basis). Two diets containing 10.6% (dry basis) MFR were formulated using the Urea Fermentation Potential (UFP) system such that in one diet N was in excess (-1.6 UFP) while in the other diet energy was in excess (+2.6 UFP). These two diets were compared in a California Net Energy trial with a feedlot diet (-.3 UFP) containing the same ingredients except the MFR. Six steers were fed in a replicated 3(2) Latin square metabolism trial and 70 steers were fed in a 118-d comparative-slaughter, feedlot trial. Digestibilities of dry matter, organic matter, crude protein, acid detergent fiber, ash, total digestible nutrients (TDN) and metabolizable energy were depressed (all P less than .05) in the MFR-containing diets. Steers fed the MFR-containing diets had lower (P less than .05) rates of gain and increased (P less than .05) feed requirements per unit gain. Net energies for maintenance and gain were slightly lower for the MFR-containing diets than the control diet. Crude protein digestibility for the MFR calculated by difference, for the -UFP and the +UFP diets were 37.8 and 50.7%, while corresponding values for TDN were 28.8 and 12.8%, respectively. Concentrations of potentially toxic elements in kidney, liver and muscle as well as flavor and tenderness of steaks were not affected by feeding MFR.

Effect of sewage sludge diets fed swine on nutrient digestibility, reproduction, growth and minerals in tissues.

Twelve female swine were fed in a 3 X 4 crossover design metabolism trial corn-soybean grower diets that contained 0, 10 or 20% sewage sludge over three 19-day periods. The mean values for total digestible nutrients were 79.4, 73.7 and 55.0%; those for metabolizable energy were 3.36, 2.25 and 1.15 Mcal/kg diet; and those for nitrogen retained were 42.8, 44.0 and 25.3%, respectively. Sewage sludge (0, 10, 20%) diets were fed to 31 sows approximately equally divided into the dietary groups during their first two pregnancies, and to their offspring from weaning until market weight. More live pigs were farrowed and weaned per litter from sows fed 20% sludge diets than from the control group. However, 21-day weaning weights of pigs were lower from sows fed the sludge-containing diets. Offspring of both first and second litters fed growing and finishing diets containing sludge from weaning until market weight had decreased daily weight gains and feed efficiency. There were no increases in nine elements (Pb, Cd, Ni, Zn, Cr, Cu, Mn, Fe and Al) in sow's milk or blood. Offspring of sows fed sludge diets showed increases of several elements in selected tissues at weaning and after consuming sludge diets until market weight.

Glutathione peroxidase acitvity in intestinal and liver tissues of rats fed various levels of selenium, sulfur and alpha-tocopherol.

The effects of various levels of selenium, alpha-tocopherol and sulfur on glutathione peroxidase (GSH-Px) activity in intestinal and liver tissues were determined in male rats fed corn-soybean or Torula yeast diets. Rats fed corn-soybean diets had greater GSH-Px activity in the small intestine, colon and liver tissues, catalase activity and selenium in the liver, and body weight gains than those fed Torula yeast diets. GSH-Px activity in the small intestine, colon, and liver tissues as well as concentration of selenium in the liver increased with increasing levels of selenium in Torula yeast diets but not with corn-soybean diets. Tocopherol supplementation had no significant effect on GSH-Px activity in rats fed Torula yeast or corn-soybean diets supplemented with selenium. Supplemental sulfur decreased GSH-Px activity in the small intestine tissues and increased activity in colon tissues.

Embryotoxicity of leukocyte extracts and its relationship to intrauterine contraception in humans.

Twelve human uteri containing intrauterine contraceptive devices (IUDs) and ten uteri without IUDs were obtained at hysterectomy. Samples of fluid were collected from the uterine lumina by absorbing the fluid in small pieces of lens paper. In the samples of luminal fluid we measured the concentration of beta-galactosidase, an enzyme which is present in human neutrophilic leukocytes and whose concentration in luminal fluid should correlate with the local inflammatory response to the intrauterine foreign body. In the samples of fluid from IUD-bearing uteri, the concentration of beta-galactosidase was significantly (P less than 0.0005) greater than that in luminal fluid from control uteri, the averages of the two groups differing by 3.8 units. To determine whether a foreign-body response of this magnitude could have any effect on preimplantation embryos, we cultured mouse embryos from day 4 to day 7 of development in culture media to which extracts of human leukocytes were added. All mouse embryos were killed when the culture media contained enough leukocyte extract to give beta-galactosidase concentrations of 0.5 unit or higher. Thus mouse embryos were killed by leukocyte extracts whose beta-galactosidase concentrations were actually less than the concentration of this marker enzyme measured in IUD uterine fluid. This comparison indicates that the luminal fluid in IUD-bearing uteri contains leukocyte break-down products in sufficient concentration to be lethal for preimplantation embryos.

Effect of papain injection on mineral concentration in tissues of roosters and hens.

A study was made of the effect of injected papain on the concentration of calcium, iron, copper, zinc and selenium in tissues of roosters and laying hens. Half the males and females were injected intravenously with a papain solution and the other half with 0.9% sodium chloride. The roosters and half the laying hens were injected one-hour ante-mortem and the others injected 24 hours ante-mortem. The laying hens had less Zn, Fe, Cu and Ca in the skeletal muscle than the roosters, and less Fe and Cu, but equivalent amounts of Ca and Zn, in the kidneys. In the roosters the kidney contained approximately five times as much Se as the muscle. The liver contained equivalent concentrations of Se in the roosters and laying hens. Papain had no effect on the concentration of any of the elements in the tissues. There was no significant difference in the concentration of the minerals between one-hour and 24-hour ante-mortem injections of the papain in the laying hens.

Endometrial carcinoma associated with Sheehan's syndrome and stilbestrol therapy.

PIP: At the age of 25, pregnant with her 2nd child, a woman was diagnosed as having pituitary necrosis resulting from hemorrhagic shock, in turn the result of a clotting defect caused by an amniotic fluid embolism. For the next 17 years, her daily replacement therapy included 50 mg ma of cortisone, 120 mg of thyroid, and .5-1 mg of diethylstilbestrol given cyclically (21 days). When an exploratory laparotomy was performed on her at age 42 because of abdominal mass,an endometrial adenocarcinoma and varying degrees of hyperplasia were found. A total abdominal hysterectomy was performed, but a year later it became clear that the patient had diffuse carcinomatosis, and 2 months later she died. Prolonged unopposed estrogen therapy is suggested as the cause of the endometrial cancer, rather than pituitary disturbance.^ieng